Substrate processing method and substrate processing apparatus

ABSTRACT

Processing of applying ultraviolet rays to a front face of an insulating film material formed on a wafer W is performed, whereby a contact angle of the front face thereof becomes smaller. Accordingly, when an insulating film material is applied on the aforesaid front face, the material smoothly spreads, and projections and depressions never occur on a front face of an upper layer insulating film material. Thereby, it is possible to form the insulating film thick and flatter on a substrate.

This application is a divisional of patent application Ser. No.09/661,309 filed Sep. 13, 2000 now U.S. Pat. No. 6,413,317.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is included in a technical field of semiconductordevice fabrication and the like, and more specifically, relates to asubstrate processing method and a substrate processing apparatus forperforming, for example, processing by ultraviolet rays for a front faceof an insulating film material applied on a substrate.

2. Description of the Related Art

In processes of semiconductor device fabrication, a layer insulatingfilm is formed, for example, by an SOD (Spin on Dielectric) system. Inthis SOD processing system, a layer insulating film is formed by coatinga wafer with a coating film while spinning the wafer and performingchemical processing, heat processing, or the like for the wafer by meansof a sol-gel process, a silk method, a speed film method, a fox method,or the like.

When a layer insulating film is formed by the sol-gel process, forexample, first an insulating film material, for example, a solution inwhich colloids of TEOS (tetraethoxysilane) are dispersed in an organicsolvent is supplied onto a semiconductor wafer (hereinafter referred toas “wafer”). Thereafter, the wafer to which the solution is supplied issubjected to gelling processing, and then solvents are exchanged.Subsequently, the wafer on which solvents are exchanged undergoes heatprocessing.

In order to form the layer insulating film, for example, thick and flaton the wafer, application of about two to three coats of an insulatingfilm material on the wafer is conventionally performed. However, thefront face of the insulating film material after the application isgenerally large in contact angle, and thus there is a problem that whenan insulating film material is further applied on the front face of theinsulating film material, a front face of an upper layer insulating filmmaterial becomes uneven.

SUMMARY OF THE INVENTION

The present invention is made under the aforesaid circumstances and anabject thereof is to provide a substrate processing method and asubstrate processing apparatus capable of forming an insulating filmthick and flatter on a substrate.

Another object of the present invention is to provide a substrateprocessing method and a substrate processing apparatus capable ofefficiently making a front face of an insulating film material smallerin contact angle.

To solve the aforesaid problem, according to a first aspect of thepresent invention, a substrate processing method, comprising the stepsof: applying an insulating film material on a substrate; performingprocessing by ultraviolet rays for a front face of the appliedinsulating film material; and further applying an insulating filmmaterial on the applied insulating film material after theultraviolet-ray processing step, is provided.

According to the above configuration, processing by ultraviolet rays,for example, processing including ultraviolet-ray irradiation isperformed for the front face of the insulating film material, wherebythe contact angle of the front face becomes smaller. Therefore, when aninsulating film material is applied on the aforesaid front face by, forexample, spin coating, the material smoothly spreads, and projectionsand depressions never occur on a front face of an upper layer insulatingfilm material. Consequently, it is possible to form the insulating filmthick and flatter on the substrate.

According to a second aspect of the present invention, a substrateprocessing method, comprising the steps of: applying an insulating filmmaterial on a substrate; applying ultraviolet rays to a front face ofthe insulating film material in an inert gas atmosphere; and thereafterbringing an atmosphere over the insulating film material to an oxygenatmosphere, is provided.

According to the above configuration, processing by ultraviolet rays,for example, processing including ultraviolet-ray irradiation isperformed for the front face of the insulating film material, wherebythe contact angle of the front face becomes small. Therefore, when amaterial of some kind is applied on the aforesaid front face by, forexample, spin coating, the material smoothly spreads, and projectionsand depressions never occur on a front face of the material.

According to a third aspect of the present invention, a substrateprocessing apparatus, comprising: a holding plate for holding asubstrate; an ultraviolet-ray irradiation lamp disposed above theholding plate for applying ultraviolet rays to a front face of thesubstrate; means for bringing a portion between the substrate held onthe holding plate and the ultraviolet-ray irradiation lamp to an inertgas atmosphere; and means for switching at least the inert gasatmosphere over the front face of the substrate held on the holdingplate to an oxygen atmosphere, is provided.

In the above configuration, the portion between the substrate held onthe holding plate and the ultraviolet-ray irradiation lamp is broughtinto the inert gas atmosphere, ultraviolet rays are applied onto thesubstrate from the ultraviolet-ray irradiation lamp, and thereafter theinert gas atmosphere over the front face of the substrate is switched tothe oxygen atmosphere, so that a front face of an insulating film can beefficiently made smaller in contact angle.

According to a fourth aspect of the present invention, a substrateprocessing apparatus, comprising: a holding plate for holding asubstrate and ascendable and descendable between a first area and asecond area below the first area; a vertically driving mechanism forvertically driving the holding plate between the first area and thesecond area; an ultraviolet-ray irradiation lamp disposed above theholding plate for applying ultraviolet rays to a front face of thesubstrate held by the holding plate; means for blasting an inert gastoward the first area; and means for blasting oxygen gas toward thesecond area, is provided.

According to the above configuration, the inert gas atmosphere can beswitched to the oxygen atmosphere only by lowering the substrate fromthe first area to the second area, and the oxygen atmosphere can beswitched to the inert gas atmosphere only by raising the substrate fromthe second area to the first area. Consequently, a front face of aninsulating film can be efficiently made smaller in contact angle byraising and lowering the substrate above the holding plate.

According to a fifth aspect of the present invention, a substrateprocessing apparatus, comprising: a holding plate for holding asubstrate to be ascendable and descendable between a first area and asecond area below the first area; a vertically driving mechanism forvertically driving the substrate held by the holding plate between thefirst area and the second area; an ultraviolet-ray irradiation lampdisposed above the holding plate for applying ultraviolet rays to afront face of the substrate held by the holding plate; means forblasting an inert gas toward the first area; and means for blastingoxygen gas toward the second area, is provided.

According to the above configuration, the inert gas atmosphere can beswitched to the oxygen atmosphere only by lowering the holding plateholding the substrate from the first area to the second area, and theoxygen atmosphere can be switched to the inert gas atmosphere only byraising the holding plate from the second area to the first area.Consequently, a front face of an insulating film can be efficiently madesmaller in contact angle by raising and lowering the holding plate.

According to a sixth aspect of the present invention, a substrateprocessing apparatus, comprising: a holding plate for holding asubstrate and rotatable; a rotationally driving mechanism forrotationally driving the holding plate; an ultraviolet-ray irradiationlamp, disposed above the holding plate along at least a radial directionof rotation of the holding plate, for applying ultraviolet rays to thesubstrate held by the holding plate; an inert gas blast portion,disposed along one side of the ultraviolet-ray irradiation lamp, forblasting an inert gas toward the front face of the substrate held on theholding plate; and an oxygen gas blast portion, disposed along the otherside of the ultraviolet-ray irradiation lamp, for blasting oxygen gastoward the front face of the substrate held on the holding plate, isprovided.

According to the above configuration, when the holding plate is rotated,the inert gas is first blasted to the front face of the substrate heldon the holding plate, whereby the front face of the substrate is broughtinto the inert gas atmosphere and then irradiated with ultraviolet rays.Thereafter, the oxygen gas is blasted to the front face of thesubstrate, whereby the front face of the substrate is brought into theoxygen atmosphere. The holding plate is continuously rotated, wherebythe aforesaid operations are repeated. Consequently, a front face of aninsulating film can be efficiently made smaller in contact angle.

These objects and still other objects and advantages of the presentinvention will become apparent upon reading the following specificationwhen taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an SOD processing system according to anembodiment of the present invention;

FIG. 2 is a front view of the SOD processing system shown in FIG. 1;

FIG. 3 is a rear view of the SOD processing system shown in FIG. 1;

FIG. 4 is a perspective view of a main wafer transfer mechanism in theSOD processing system shown in FIG. 1;

FIG. 5 is a front view showing the structure of an ultraviolet-rayprocessing station according to a first embodiment of the presentinvention;

FIG. 6 is a processing flowchart of the SOD processing system shown inFIG. 1;

FIG. 7 is a front view showing the structure of an ultraviolet-rayprocessing station according to a second embodiment of the presentinvention;

FIG. 8 is a front view showing the structure of an ultraviolet-rayprocessing station according to a third embodiment of the presentinvention;

FIG. 9 is a front view showing the structure of an ultraviolet-rayprocessing station according to a fourth embodiment of the presentinvention;

FIG. 10 is a plan view of the ultraviolet-ray processing station shownin FIG. 9;

FIG. 11 is a plan view of a low-oxygen curing and cooling processingstation;

FIG. 12 is a sectional view of the low-oxygen curing and coolingprocessing station shown in FIG. 11;

FIG. 13 is a front view showing the structure of an ultraviolet-rayprocessing station according to a fifth embodiment of the presentinvention; and

FIG. 14 is a sectional view of a low-oxygen curing and coolingprocessing station according to an eighth embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, a first embodiment of the present invention will bedescribed with reference to the drawings.

In this first embodiment, a substrate processing method of the presentinvention is applied to an SOD (Spin on Dielectric) processing systemfor forming a layer insulating film on a wafer. FIG. 1 to FIG. 3 areviews showing the entire structure of the SOD processing system, FIG. 1is a plan view, FIG. 2 is a front view, and FIG. 3 is a rear view.

The SOD processing system 1 has a structure in which a cassette block 10for transferring a plurality of, for example, 25 semiconductor wafers(hereinafter, referred to as wafers) W as substrates, as a unit, in awafer cassette CR from/to the outside into/from the system and carryingthe wafer W into/out of the wafer cassette CR, a processing block 11 inwhich various kinds of processing stations each for performingpredetermined processing for the wafers W one by one in an SOD coatingprocess are multi-tiered at predetermined positions, and a cabinet 12 inwhich a bottle of ammonia water, a bubbler, a drain bottle, and the likerequired in an aging process are provided are integrally connected.

In the cassette block 10, as shown in FIG. 1, a plurality of, forexample, up to four wafer cassettes CR are mounted with respective wafertransfer ports facing the processing block 11 side at positions ofprojections 20 a on a cassette mounting table 20 in a line in anX-direction. A wafer transfer body 21 movable in the direction ofarrangement of cassettes (the X-direction) and in the direction ofarrangement of wafers housed in the wafer cassette CR (a Z-verticaldirection) selectively gets access to each of the wafer cassettes CR.The wafer transfer body 21 is structured to be rotatable in aθ-direction so as to be accessible to a transfer and chill plate (TCP)included in a multi-tiered station section of a third group G3 on theprocessing block 11 side as will be described later.

In the processing block 11, as shown in FIG. 1, a vertical transfer-typemain wafer transfer mechanism 22 is provided at the central portionthereof. Around the main wafer transfer mechanism 22, all processingstations composing one group or a plurality of groups are multi-tiered.In this embodiment, four groups G1, G2, G3, and G4 each havingmulti-tiered stations are arranged. Multi-tiered stations of the firstand second groups G1 and G2 are arranged side by side on the front sideof the system (the lower side in FIG. 1), multi-tiered stations of thethird group G3 are arranged adjacent to the cassette block 10, andmulti-tiered stations of the fourth group G4 are arranged adjacent tothe cabinet 12.

As shown in FIG. 2, in the first group G1, an SOD coating processingstation (SCT) for supplying an insulating film material while the waferW is mounted on a spin chuck in a cup CP and applying a uniforminsulating film material on the wafer by rotating the wafer and asolvent exchange processing station (DSE) for supplying chemicals forexchange such as HMDS, heptane, and the like while the wafer W ismounted on a spin chuck in a cup CP and exchanging a solvent in theinsulating film applied on the wafer for another solvent prior to adrying process are two-tiered from the bottom in order.

In the second group G2, an SOD coating processing station (SCT) isarranged at the upper tier. Incidentally, it is possible to arrange anSOD coating processing station (SCT), a solvent exchange processingstation (DSE), or the like at the lower tier of the second group G2 ifnecessary.

As shown in FIG. 3, in the third group G3, two low-oxygen andhigh-temperature heat processing stations (OHP), a low-temperature heatprocessing station (LHP), two cooling processing stations (CPL), atransfer and chill plate (TCP), and a cooling processing station (CPL)are multi-tiered from the top in order. The low-oxygen andhigh-temperature heat processing station (OHP) here has a hot plate onwhich the wafer W is mounted inside a sealable processing chamber,exhausts air from the center of the top portion of the processingchamber while N₂ is being discharged uniformly from holes at the outerperiphery of the hot plate, and performs high-temperature heatprocessing for the wafer W in a low-oxygen atmosphere. Thelow-temperature heat processing station (LHP) has a hot plate on whichthe wafer W is mounted and performs low-temperature heat processing forthe wafer W. The cooling processing station (CPL) has a chill plate onwhich the wafer W is mounted and performs cooling processing for thewafer W. The transfer and chill plate (TCP) has a two-tiered structurewith a chill plate for cooling the wafer W at the lower tier and adelivery table at the upper tier and performs transfer of the wafer Wbetween the cassette block 10 and the processing block 11.

In the fourth group G4, a low-temperature heat processing station (LHP),a low-oxygen curing and cooling processing station (DCC), anultraviolet-ray processing station (UV) according to the presentinvention, a low-oxygen curing and cooling processing station (DCC), andan aging processing station (DAC) are multi-tiered from the top inorder. The low-oxygen curing and cooling processing station (DCC) herehas a hot plate and a chill plate such that they are adjacent to eachother inside a sealable processing chamber, and performshigh-temperature heat processing for the wafer W in the low-oxygenatmosphere in which exchange for N₂ is performed and performs coolingprocessing for the wafer W which has been subjected to the heatprocessing. The aging processing station (DAC) introduces a processinggas (NH₃+H₂O) made by mixture of ammonia gas and water vapor into asealable processing chamber to perform aging processing for the wafer W,thereby wet-gelling an insulating film material on the wafer W. Theultraviolet-ray processing station (UV) will be described later. Theultraviolet-ray processing station (UV) is disposed between twolow-oxygen curing and cooling processing stations (DCC), whereby theinside of the station can be kept at a stable temperature.

FIG. 4 is a perspective view showing the appearance of the main wafertransfer mechanism 22. This main wafer transfer mechanism 22 is providedwith a wafer transfer device 30 which is ascendable and descendable inthe vertical direction (the Z-direction) inside a cylindrical supporter27 composed of a pair of wall portions 25 and 26 which are connectedwith each other at respective upper ends and lower ends and face eachother. The cylindrical supporter 27 is connected to a rotating shaft ofa motor 31 and rotates integrally with the wafer transfer device 30around the aforesaid rotating shaft by rotational driving force of themotor 31. Accordingly, the wafer transfer device 30 is rotatable in theθ-direction. For example, three tweezers are provided on a transfer base40 of the wafer transfer device 30. These tweezers 41, 42, and 43 eachhave a shape and a size capable of freely passing through a side opening44 between both the wall portions 25 and 26 of the cylindrical supporter27 so as to be movable back and forth along the X-direction. The mainwafer transfer mechanism 22 allows the tweezers 41, 42, and 43 to getaccess to processing stations disposed thereabout to transfer the waferW from/to these processing stations.

It should be noted that this SOD processing system 1 is placed in aclean room by way of example, and an atmosphere over the main wafertransfer mechanism 22 is set at, for example, a pressure higher thanthat of the clean room which is set at atmospheric pressure, therebyejecting particles which occur above the main wafer transfer mechanism22 to the outside of the SOD processing system 1 and additionallypreventing particles in the clean room from entering the SOD processingsystem 1.

FIG. 11 is a plan view showing the structure of the low-oxygen curingand cooling processing station (DCC) having a heat processing chamberand a cooling processing chamber, and FIG. 12 is a sectional viewthereof.

The low-oxygen curing and cooling processing station (DCC) includes aheat processing chamber 151 and a cooling processing chamber 152 whichis provided adjacent to the heat processing chamber 151.

The heat processing chamber 151 includes a processing chamber main body153 of which the top portion is opened and a lid body 154 disposed to beascendable and descendable so as to open and close the top openingportion of the processing chamber main body 153. A raising and loweringcylinder 155 is connected with the lid body 154, so that the lid body154 is raised and lowered by drive of the raising and lowering cylinder155. The top opening portion of the processing chamber main body 153 isclosed with the lid body 154, whereby a sealed space is formed in theheat processing chamber 151. Further, delivery of the wafer W isperformed between the heat processing chamber 151 and the main wafertransfer mechanism 22 and between the heat processing chamber 151 andthe cooling processing chamber 152 with the top portion of theprocessing chamber main body 153 being opened.

A hot plate 156 for performing heat processing for the wafer W isdisposed nearly at the central portion of the processing chamber mainbody 153. In the hot plate 156, for example, a heater (not shown) isembedded, and the set temperature thereof can be, for example, 200° C.to 470° C. Further, a plurality of, for example, three holes 157concentrically and vertically penetrate the hot plate 156, and supportpins 158 for supporting the wafer W are inserted in the holes 157 to beascendable and descendable. The support pins 158 are connected to acommunicating member 159 into one body under the rear face of the hotplate 156, and the communicating member 159 is raised and lowered by araising and lowering cylinder 160 disposed thereunder. The support pins158 protrude and retract from the front face of the hot plate 156 byraising and lowering operation of the raising and lowering cylinder 160.

Moreover, a plurality of proximity pins 161 are disposed on the frontface of the hot plate 156, thereby preventing the wafer W from directlycontacting the hot plate 156 when heat processing is performed for thewafer W. Thereby, electrostatic is prevented from building up in thewafer W during the heat processing.

Furthermore, a ring pipe 163 provided with a large number of gas blastports 162 for supplying an inert gas, for example, nitrogen gas (N₂)into the heat processing chamber 151 is disposed to surround theperiphery of the hot plate 156. This ring pipe 163 is connected to anitrogen gas cylinder 165 via a pipe 164, and an open/close valve 166 isplaced on the pipe 164, and the open/close valve 166 is configured suchthat its opening and closing is controlled by a control section 167. Itshould be noted that not only an inert gas, but also another gas, forexample, oxygen gas may be supplied into the heat processing chamber 151as required. In that case, it is possible to supply these gasses via aswitching valve for switching between nitrogen gas and oxygen gassharing the ring pipe 163. Thereby, upsizing of the heat processingchamber can be avoided.

Meanwhile, an exhaust port 168 for reducing pressure is provided nearlyat the central portion of the lid body 154, and the exhaust port 168 isconnected to a vacuum pump 170 via a flexible hose 169 by way ofexample. By operation of the vacuum pump 170, the inside of the heatprocessing chamber 151 can be set at a pressure lower than atmosphericpressure, for example, about 0.1 torr.

Further, a current plate 171 is disposed inside the lid body 154 tocover the exhaust port 168. The current plate 171 is larger in diameterthan the exhaust port 168 and has a clearance of, for example, about 5mm between the current plate 171 and the inner wall of the lid body 154.By virtue of the arrangement of such a current plate 171, the pressurein the heat processing chamber 151 can be uniformly reduced.

Moreover, attached to the lid body 154 is a pressure sensor 172 formeasuring the pressure in the heat processing chamber 151. A measuredresult by the pressure sensor 172 is reported to the control section167, and the control section 167 controls the operation of the vacuumpump 170 based on the measured result to thereby keep the inside of theheat processing chamber 151 at a state of a fixed reduced pressure.

The cooling processing chamber 152 is provided with an opening portion173, facing the heat processing chamber 151, for performing delivery ofthe wafer W from/to the heat processing chamber 151. The opening portion173 can be opened and closed by a shutter member 174. The shutter member174 is raised and lowered for the aforesaid open and close by means of araising and lowering cylinder 175.

Further, in the cooling processing chamber 152, a chill plate 176 forcooling the wafer W while the wafer W is mounted thereon is configuredto be movable in a horizontal direction along a guide plate 177 a bymeans of a moving mechanism 177 b. Thereby, the chill plate 176 can getinto the heat processing chamber 151 through the opening portion 173,receives the wafer W in the heat processing chamber 151 which has beenheated by the hot plate 156 from the support pins 158, carries the waferW into the cooling processing chamber 152, and returns the wafer W tothe support pins 158 after the wafer W is cooled. It should be notedthat the set temperature of the chill plate 176 is, for example, 15° C.to 25° C. and an applicable temperature range of the wafer W to becooled is 200° C. to 470° C.

Furthermore, an inert gas such as nitrogen gas or the like is suppliedinto the cooling processing chamber 152 from the top thereof via a pipe178. At the lower portion of the cooling processing chamber 152 providedis an exhaust port 179 which is connected to a vacuum pump 181, forexample, via a flexible hose 180. By operation of the vacuum pump 181,the inside of the cooling processing chamber 152 can be set at apressure lower than atmospheric pressure, for example, about 0.1 torr.Incidentally, the vacuum pump used in the heat processing chamber 151and the vacuum pump used in the cooling processing chamber 152 may becomposed of the same apparatus.

FIG. 5 is a front view showing the structure of the ultraviolet-rayprocessing station (UV) according to the present invention.

As shown in FIG. 5, in the ultraviolet-ray processing station (UV), aholding plate 51 for holding the wafer W is disposed nearly at thecenter thereof. The holding plate is provided with a plurality of, forexample, three support pins 52. The delivery of the wafer W to/from thetweezers 41, 42, and 43 of the main wafer transfer mechanism 22 isperformed on the support pins 52, and the wafer W is subjected toprocessing by ultraviolet rays while supported by the support pins 52.

An ultraviolet-ray irradiation lamp 53 for applying ultraviolet rays tothe front face of the wafer W held by the holding plate 51 is placedabove the holding plate 51. On one side of those, disposed is a blastpipe 55 having a blast port 54 for blasting gas toward a clearancebetween the holding plate 51 and the ultraviolet-ray irradiation lamp53. A switching valve 56 is connected to the blast pipe 55. Theswitching valve 56 performs switching for supplying one of nitrogen gasas an inert gas which is supplied from a nitrogen gas cylinder of whichthe illustration is omitted and oxygen gas which is supplied from anoxygen gas cylinder of which the illustration is omitted to the blastpipe 55 under the control of a control section 57.

Further, a vertically driving mechanism 58 for vertically driving theultraviolet-ray irradiation lamp 53 is disposed above theultraviolet-ray irradiation lamp 53, and, for example, an illuminancemonitor 59 for monitoring an illuminance of the ultraviolet-rayirradiation lamp 53 is disposed near the holding plate 51. A monitoredresult by the illuminance monitor 59 is sent to the control section 57,and the control section 57 allows the vertically driving mechanism 58 toraise and lower the ultraviolet-ray irradiation lamp 53 so as to keepthe monitored illuminance constant. Thereby, the illuminance of theultraviolet rays applied to the wafer W can be usually kept constant. Itshould be noted that such a control of illuminance can be realized byraising and lowering the holding plate 51 and not the ultraviolet-rayirradiation lamp 53.

Next, operations in the SOD processing system 1 thus structured will beexplained. FIG. 6 shows a processing flow in this SOD processing system1.

First, in the cassette block 10, the unprocessed wafer W is transferredfrom the wafer cassette CR to the delivery table in the transfer andchill plate (TCP) included in the third group G3 on the processing block11 side by means of the wafer transfer body 21.

The wafer W transferred to the delivery table in the transfer and chillplate (TCP) is transferred to the cooling processing station (CPL) bymeans of the main wafer transfer mechanism 22. In the cooling processingstation (CPL), the wafer W is cooled to a temperature suitable forprocessing in the SOD coating processing station (SCT) (step 601).

The wafer W which has undergone the cooling processing in the coolingprocessing station (CPL) is transferred to the SOD coating processingstation (SCT) via the main wafer transfer mechanism 22. In the SODcoating processing station (SCT), the wafer W is subjected to SODcoating processing (step 602).

The wafer W which has undergone the SOD coating processing in the SODcoating processing station (SCT) is transferred to the aging processingstation (DAC) via the main wafer transfer mechanism 22 and subjected toaging processing, whereby an insulating film material on the wafer W isgelled (step 603).

The wafer W which has undergone the aging processing in the agingprocessing station (DAC) is transferred to the solvent exchangeprocessing station (DSE) via the main wafer transfer mechanism 22. Inthe solvent exchange processing station (DSE), a chemical for exchangeis supplied to the wafer W and processing for exchanging a solvent inthe insulating film applied on top of the wafer for another solvent isperformed (step 604).

The wafer W which has undergone the exchange processing in the solventexchange processing station (DSE) is transferred to the low-temperatureheat processing station (LHP) by means of the main wafer transfermechanism 22. In the low-temperature heat processing station (LHP), thewafer W undergoes low-temperature heat processing (step 605).

The wafer W which has undergone the low-temperature heat processing inthe low-temperature heat processing station (LHP) is transferred to theultraviolet-ray processing station (UV) by means of the main wafertransfer mechanism 22. In the ultraviolet-ray processing station (UV),the wafer W is subjected to processing by ultraviolet rays with awavelength of about 172 nm (step 606). In this processing by ultravioletrays, nitrogen gas is first blasted from the blast port 54 of the blastpipe 55, whereby the inside of the ultraviolet-ray processing station(UV) is brought to a nitrogen gas atmosphere, and in that state,ultraviolet rays are applied, for example, for one minute from theultraviolet-ray irradiation lamp 53 (step 606 a). Next, oxygen gas isblasted from the blast port 54 of the blast pipe 55, whereby the insideof the ultraviolet-ray processing station (UV) is brought to an oxygengas atmosphere, for example, for ten seconds (step 606 b). As describedabove, in this embodiment, ultraviolet rays are applied to the frontface of the insulating film material applied on the wafer W in thenitrogen atmosphere, and thereafter the atmosphere over the front faceof the insulating film material is brought to an oxygen gas atmosphereto generate oxygen radicals (O*), so that the front face of theinsulating film can be efficiently made smaller in contact angle.Incidentally, the above-described step 606 a and step 606 b may beperformed several times. As for the oxygen gas atmosphere here in thepresent invention, oxygen is suitably contained at least 5% or more inthe gas. Though 100% of oxygen gas is used in this embodiment, air canbe used instead. Further, the ultraviolet-ray irradiation lamp and thewafer W are separated by about 5 mm in this embodiment.

Thereafter, nitrogen gas is blasted for about 30 seconds from the blastport 54 of the blast pipe 55, whereby the inside of the ultraviolet-rayprocessing station (UV) is exchanged for a nitrogen gas atmosphere.

The wafer W which has been subjected to the processing by ultravioletrays is transferred to the cooling processing station (CPL) by means ofthe main wafer transfer mechanism 22. In the cooling processing station(CPL), the wafer W is cooled (step 607).

The wafer W which has undergone the cooling processing in the coolingprocessing station (CPL) is transferred again to the SOD coatingprocessing station (SCT) via the main wafer transfer mechanism 22. Inthe SOD coating processing station (SCT), the wafer W is subjected to asecond time of SOD coating processing (step 608). At that time, thefront face of the insulating film material which has been alreadyapplied on the wafer W is improved in quality so as to be smaller incontact angle by the aforesaid processing by ultraviolet rays, and thuseven if an insulating film material is further applied thereon,projections and depressions do not occur on a front face thereof.

The wafer W which has undergone the SOD coating processing in the SODcoating processing station (SCT) is transferred to the aging processingstation (DAC) via the main wafer transfer mechanism 22 and subjected toaging processing, whereby the insulating film material on the wafer W isgelled (step 609).

The wafer W which has undergone the aging processing in the agingprocessing station (DAC) is transferred to the solvent exchangeprocessing station (DSE) via the main wafer transfer mechanism 22. Inthe solvent exchange processing station (DSE), a chemical for exchangeis supplied to the wafer W and processing for exchanging a solvent inthe insulating film applied on top of the wafer for another solvent isperformed (step 610).

The wafer W which has undergone the exchange processing in the solventexchange processing station (DSE) is transferred to the low-temperatureheat processing station (LHP) by means of the main wafer transfermechanism 22. In the low-temperature heat processing station (LHP), thewafer W undergoes low-temperature heat processing (step 611).

The wafer W which has undergone the low-temperature heat processing inthe low-temperature heat processing station (LHP) is transferred to thelow-oxygen and high-temperature heat processing station (OHP) by meansof the main wafer transfer mechanism 22. In the low-oxygen andhigh-temperature heat processing station (OHP), the wafer W undergoeshigh-temperature heat processing in a low-oxygen atmosphere (step 612).

The wafer W which has undergone the high-temperature heat processing inthe low-oxygen and high-temperature heat processing station (OHP) istransferred to the low-oxygen curing and cooling processing station(DCC) by means of the main wafer transfer mechanism 22. In thelow-oxygen curing and cooling processing station (DCC), the wafer Wundergoes high-temperature heat processing in a low-oxygen atmosphereand then cooling processing (step 613).

Here, the processing in the step 613 will be explained in more detailusing FIG. 11 and FIG. 12.

The wafer W is delivered from the main wafer transfer mechanism 22 ontothe support pins 58 in a state in which the top portion of theprocessing chamber main body 153 is opened and the support pins 158protrude from the front face of the hot plate 156. At that time,nitrogen gas is blasted into the heat processing chamber 151 from thegas blast ports 162 of the ring pipe 163, whereby the inside of the heatprocessing chamber 151 is set at a pressure higher than a pressure onthe main wafer transfer mechanism 22 side. Thereby, it is avoided forparticles to be drawn from the main wafer transfer mechanism 22 sideinto the heat processing chamber 151.

Subsequently, the lid body 154 is lowered and the top opening portion ofthe processing chamber main body 153 is closed with the lid body 154,thereby forming a sealed space in the heat processing chamber 151. Then,a blast of nitrogen gas into the heat processing chamber 151 from thegas blast ports 162 of the ring pipe 163 is stopped and the vacuum pump170 is operated to set the inside of the heat processing chamber 151 ata pressure lower than atmospheric pressure, for example, about 0.1 torr.Thereafter, the support pins 158 are lowered and retract from the frontface of the hot plate 156, whereby the wafer W is mounted on the hotplate 156 and heat processing for the wafer W is started. Since thewafer W is subjected to the heat processing at a pressure lower thanatmospheric pressure in the heat processing chamber 151 as describedabove, it is possible to quickly perform the heat processing performedfor the wafer W and to form a layer insulating film which is high indielectric constant and is a uniform porous film on the wafer W.

Next, the blast of nitrogen gas is started into the heat processingchamber 151 from the gas blast ports 162 of the ring pipe 163 to purgethe inside of the heat processing chamber 151 by the nitrogen gas, thesupport pins 158 are raised to protrude from the front face of the hotplate 156, and the lid body 154 is raised, whereby the top portion ofthe processing chamber main body 153 is opened. The blast of thenitrogen gas into the heat processing chamber 151 from the gas blastports 162 of the ring pipe 163 is continued during that time. Thereby,particles are never drawn from the main wafer transfer mechanism 22 sideinto the heat processing chamber 151.

Next, the chill plate 176 in the cooling processing chamber 152 getsinto the heat processing chamber 151 through the opening portion 173,receives the wafer W from the support pins 158, and carries the wafer Winto the cooling processing chamber 152. During that time, nitrogen gasis supplied into the cooling processing chamber 152 through the pipe178. Thereby, oxidation of the wafer W is prevented. For example,nitrogen gas is supplied to the cooling processing chamber 152 too muchto thereby bring the inside of the cooling processing chamber 152 morepositive in pressure than the inside of the heat processing chamber 151,whereby it is avoided for particles to be drawn into the coolingprocessing chamber 152. Contrary to that, nitrogen gas is supplied tothe cooling processing chamber 152 too little to thereby bring theinside of the cooling processing chamber 152 more negative in pressurethan the inside of the heat processing chamber 151, whereby it isavoided for particles to be drawn into the heat processing chamber 151.In other words, the essence is to control drawing of particles by givinga relation of negative pressure or positive pressure between the heatprocessing chamber 151 and the cooling processing chamber 152.

Next, the opening portion 173 is closed by the shutter member 174, andthe supply of nitrogen gas into the cooling processing chamber 152 isstopped. Further, the inside of the cooling processing chamber 152 isset to a pressure lower than atmospheric pressure by the operation ofthe vacuum pump 181, and the cooling processing for the wafer W isperformed. The cooling processing is performed under the reducedpressure as described above, whereby the cooling processing can bequickly and uniformly performed for the wafer W.

Next, the operation of the vacuum pump 181 is stopped, the supply ofnitrogen gas into the cooling processing chamber 152 is started, and theopening portion 173 is opened. The chill plate 176 gets into the heatprocessing chamber 151 through the opening portion 173 and delivers thewafer W to the support pins 158. At that time, the blast of nitrogen gasinto the heat processing chamber 151 from the gas blast ports 162 of thering pipe 163 is continued. Thereby, particles are never drawn from themain wafer transfer mechanism 22 side into the heat processing chamber151.

The wafer W which has been subjected to the processing in the low-oxygencuring and cooling processing station (DCC) is transferred to the chillplate in the transfer and chill plate (TCP) by means of the main wafertransfer mechanism 22. The wafer W undergoes cooling processing on thechill plate in the transfer and chill plate (TCP) (step 614). In thisembodiment, an insulating film with a thickness of about 500 nm can beobtained by one time of SOD coating processing and thus an insulatingfilm with a thickness of 1 μm can be obtained by a total of two times ofSOD coating processing.

The wafer W which has undergone the cooling processing on the chillplate in the transfer and chill plate (TCP) is transferred to the wafercassette CR via the wafer transfer body 21 in the cassette block 10.

By the above-described SOD processing, a flat layer insulating filmwithout projections and depressions can be formed on the front face ofthe wafer W.

Next, a second embodiment of an ultraviolet-ray processing stationaccording to the present invention will be explained.

FIG. 7 is a front view showing the structure of the ultraviolet-rayprocessing station (UV) according to the second embodiment.

In the ultraviolet-ray processing station (UV) shown in FIG. 7, aholding plate 71 for holding the wafer W is disposed nearly at thecenter thereof. The holding plate 71 is provided with a plurality, forexample, three support pins 72. The support pins 72 are configured to beraised and lowered above the holding plate 71 by means of a verticallydriving mechanism 73 which is provided on the rear face side of theholding plate 71. Further, an ultraviolet-ray irradiation lamp 74 isdisposed above the front face of the wafer W held by the holding plate71. Here, an area close to the ultraviolet-ray irradiation lamp 74 isregarded as a first area {circle around (1)}, and an area close to theholding plate 71 thereunder is regarded as a second area {circle around(2)}. On one side of these areas, a nitrogen gas blast pipe 75 forblasting nitrogen gas as an inert gas supplied from a nitrogen gascylinder of which the illustration is omitted toward the first area{circle around (1)} is disposed, and an oxygen gas blast pipe 76 forblasting oxygen gas supplied from an oxygen gas cylinder of which theillustration is omitted toward the second area {circle around (2)} isdisposed under the first area {circle around (1)}. Nitrogen gas of lowmolecular weight is blasted to the first area {circle around (1)} andoxygen gas of high molecular weight is blasted to the second area{circle around (2)} under the first area {circle around (1)} asdescribed above, thereby reducing mixture of nitrogen gas in the firstarea {circle around (1)} and oxygen gas in the second area {circlearound (2)}.

In a state in which the tips of the support pins 72 are within the firstarea {circle around (1)}, the wafer W is delivered from the tweezers 41,42, and 43 of the main wafer transfer mechanism 22 to the support pins72. Then, ultraviolet rays are applied to the front face of the wafer Wfrom the ultraviolet-ray irradiation lamp 74 in the first area {circlearound (1)}. Thereafter, the support pins 72 are lowered, whereby thewafer W is moved to the second area {circle around (2)}, and oxygenradicals (O*) are generated in the second area {circle around (2)}.Incidentally, the above-described raising and lowering operation may berepeated twice or more.

As described above, in this embodiment, a nitrogen gas atmosphere can beswitched to an oxygen gas atmosphere only by lowering the wafer W fromthe first area {circle around (1)} to the second area {circle around(2)}, and an oxygen gas atmosphere can be switched to a nitrogen gasatmosphere only by raising the wafer W from the second area {circlearound (2)} to the first area {circle around (1)}. Consequently, thefront face of the insulating film applied on the wafer W can beefficiently made smaller in contact angle.

It should be noted that in the second embodiment, the support pins 72are raised and lowered to thereby move the wafer W between the firstarea {circle around (1)} and the second area {circle around (2)}.However, it is also suitable to configure that support pins 82 providedat a holding plate 81 are fixed and the holding plate 81 itself israised and lowered by a vertically driving mechanism 83 as shown in FIG.8 as a third embodiment. In FIG. 8, the same numerals and symbols aregiven to the same components as those shown in FIG. 7.

Next, a fourth embodiment of an ultraviolet-ray processing stationaccording to the present invention will be explained.

FIG. 9 is a front view showing the structure of the ultraviolet-rayprocessing station (UV) according to the fourth embodiment, and FIG. 10is a plan view thereof.

In the ultraviolet-ray processing station (UV) shown in these drawings,a holding plate 91 for holding the wafer W is disposed nearly at thecenter thereof. The holding plate 91 is provided with a plurality of,for example, three support pins 92. The holding plate 91 is rotated bymeans of a rotationally driving mechanism 93 which is disposed on therear face side thereof.

Further, an oblong ultraviolet-ray irradiation lamp 94 is disposed abovethe holding plate 91 along a direction of a diameter of rotation of theholding plate 91.

An oblong nitrogen gas blast nozzle 95 as an inert gas blast portion forblasting nitrogen gas toward the front face of the wafer W held on theholding plate 91 is disposed along one radial direction from an areaclose to the center on one side of the ultraviolet-ray irradiation lamp94, and an oblong oxygen gas blast nozzle 96 as an oxygen gas blastportion for blasting oxygen gas toward the front face of the wafer Wheld on the holding plate 91 is disposed along the aforesaid one radialdirection from an area close to the center on the other side of theultraviolet-ray irradiation lamp 94. Similarly, an oblong oxygen gasblast nozzle 97 for blasting oxygen gas toward the front face of thewafer W held on the holding plate 91 is disposed along the other radialdirection from an area close to the center on the one side of theultraviolet-ray irradiation lamp 94, and an oblong nitrogen gas blastnozzle 98 for blasting nitrogen gas toward the front face of the wafer Wheld on the holding plate 91 is disposed along the aforesaid otherradial direction from an area close to the center on the other side ofthe ultraviolet-ray irradiation lamp 94.

When the holding plate 91 is rotated in a direction of arrows in FIG.10, nitrogen gas is first blasted to the front face of the wafer W,whereby the front face of the wafer W is in a nitrogen gas atmosphereand then irradiated with ultraviolet rays. Thereafter, oxygen gas isblasted to the front face of the wafer W, whereby the front face of thewafer W is brought into an oxygen gas atmosphere, and oxygen radicalsare generated. The holding plate 91 is continuously rotated, whereby theaforesaid operations are repeated. Consequently, according to thisembodiment, the front face of the insulating film on the wafer can beefficiently made smaller in contact angle.

Next, a fifth embodiment of an ultraviolet-ray processing stationaccording to the present invention will be explained.

FIG. 13 is a front view showing the structure of the ultraviolet-rayprocessing station (UV) according to the fifth embodiment.

In the ultraviolet-ray processing station (UV) according to the fifthembodiment, a hot plate 251 is used as the holding plate 51 of theultraviolet-ray processing station (UV) according to the firstembodiment. The hot plate 251 can be heated to a temperature of about120° C., and the wafer W is mounted on the hot plate 251 which is set ata temperature of 120° C. while ultraviolet rays are applied to the waferW in the fifth embodiment. The wafer W is irradiated with ultravioletrays while heated as described above, whereby generation of oxygenradicals (O*) is accelerated more, with the result that a period of timeof ultraviolet-ray irradiation can be reduced as compared with the firstembodiment.

Next, a sixth embodiment according to the present invention will beexplained.

In the first embodiment, the inside of the ultraviolet-ray processingstation (UV) is brought to an oxygen gas atmosphere after a nitrogen gasatmosphere during ultraviolet-ray irradiation. In the sixth embodiment,the inside of the ultraviolet-ray processing station (UV) is brought toa mixed gas atmosphere made by mixture of 95% of nitrogen gas and 5% ofoxygen gas during the ultraviolet-ray irradiation. The mixture ratio ofan inert gas and oxygen gas is limited as described above, therebykeeping a propagation efficiency of ultraviolet rays good andefficiently making the front face of the insulating film smaller incontact angle without inhibiting generation of oxygen radicals (O*).Accordingly, the operation of switching the atmosphere in theultraviolet-ray processing station (UV) during ultraviolet-rayirradiation as in the first embodiment becomes unnecessary, resulting inimproved operating efficiency. Further, a period of processing time inthe ultraviolet-ray processing station (UV) is 1 minute 40 seconds inthe first embodiment, but it can be reduced to 1 minute 10 seconds inthe sixth embodiment.

Next, a seventh embodiment according to the present invention will beexplained.

In the first embodiment, the inside of the ultraviolet-ray processingstation (UV) is set to be switched to an oxygen gas atmosphere after anitrogen gas atmosphere during ultraviolet-ray irradiation. In theseventh embodiment, the atmosphere in the ultraviolet-ray processingstation (UV) is set such that oxygen gas therein is gradually increased.For example, the setting is made such that nitrogen gas is supplied intothe ultraviolet-ray processing station (UV) at the time of start ofultraviolet-ray irradiation, a mixed gas of nitrogen gas and oxygen gasis supplied into the ultraviolet-ray processing station (UV) with oxygengas being gradually increased with time, and the mixture ratio of themixed gas becomes a ratio of 95% of nitrogen gas to 5% of oxygen gas atthe time of completion of the ultraviolet-ray irradiation. Ultravioletrays are applied with oxygen gas being gradually increased as above,whereby when the inside of the ultraviolet-ray processing station (UV)is exchanged for a nitrogen gas atmosphere after the ultraviolet-rayirradiation, a period of time for purging nitrogen gas can be shortened.

Next, an eighth embodiment according to the present invention will beexplained.

The ultraviolet-ray processing station (UV) is provided to performultraviolet-ray processing in the first embodiment. However, it ispossible to provide ultraviolet-ray irradiation means in the coolingprocessing chamber in the low-oxygen curing and cooling processingstation (DCC) and to perform the ultraviolet-ray processing which isperformed in the step 606 in the cooling processing chamber in thelow-oxygen curing and cooling processing station (DCC).

FIG. 14 is a sectional view of a low-oxygen curing and coolingprocessing station (DCC) according to the eighth embodiment. In FIG. 14,an ultraviolet-ray irradiation lamp 53 is disposed above a chill plate176 in a cooling processing chamber 152 of the low-oxygen curing andcooling processing station (DCC). Further, a blast pipe 255 including ablast port 254 for blasting gas toward a clearance between the chillplate 176 and the ultraviolet-ray irradiation lamp 53 is disposed. Aswitching valve 256 is connected to the blast pipe 255. The switchingvalve 256 performs switching for supplying one of nitrogen gas as aninert gas and oxygen gas which is supplied from an oxygen gas cylinderto the blast pipe 255 under the control of the control section.

The ultraviolet-ray irradiation means is provided in the coolingprocessing chamber of the low-oxygen curing and cooling processingstation (DCC), whereby processing in the step 606 and the step 613 canbe performed in the same station.

Nitrogen gas is used as an inert gas in the aforesaid embodiments, butargon gas or the like can also be used. Attenuation of ultraviolet rayswhich propagate in gas is smaller and energy efficiency is better in thecase where argon gas is used than in the case where nitrogen gas isused.

The aforesaid embodiments have the intention of clarifying technicalmeaning of the present invention. Therefore, the present invention isnot intended to be limited to the above concrete embodiments and to beinterpreted in a narrow sense, and various changes may be made thereinwithout departing from the spirit of the present invention and withinthe meaning of the claims.

What is claimed is:
 1. A substrate processing method, comprising thesteps of: applying an insulating film material on a substrate;performing processing by ultraviolet rays for a front face of theapplied insulating material, the ultraviolet rays being applied to thefront face of the applied insulating film material in an inertatmosphere and thereafter in an oxygen atmosphere switched from theinert gas atmosphere; and further applying an insulating film materialon the applied insulating film material after the ultraviolet-rayprocessing step.
 2. The method as set forth in claim 1, wherein theoxygen atmosphere is an atmosphere with an oxygen content of 5% or more.3. The method as set forth in claim 1, wherein heat processing isperformed for the substrate after said insulating film material coatingstep and before said ultraviolet-ray processing step, and whereincooling processing is performed for the substrate after saidultraviolet-ray processing step and before said further insulating filmmaterial coating step.
 4. The method as set forth in claim 1, whereinthe oxygen is contained 5% in the mixed gas.
 5. The method as set forthin claim 1, wherein the ultraviolet-ray processing step is performedunder an atmosphere of which oxygen content is gradually increased. 6.The method as set forth in claim 1, wherein heat processing is beingperformed for the substrate during said ultraviolet-ray processing step.7. A substrate processing method, comprising the steps of: applying aninsulating film material on a substrate; and applying ultraviolet raysto a front face of the insulating film material in an inert gasatmosphere; and thereafter in an oxygen atmosphere switched from theinert gas.
 8. A substrate processing method, comprising the steps of:applying an insulating film material on a substrate; applyingultraviolet rays to a front face of the insulating film material in aprocessing chamber with an inert gas atmosphere; thereafter applyingultraviolet rays to the front face of the insulating film material underan atmosphere in the processing chamber into which oxygen has beenallowed to flow; and bringing the inside of the processing chamber to aninert gas atmosphere.
 9. A substrate processing method, comprising thesteps of: applying an insulating film material on a substrate;performing processing by ultraviolet rays for a front face of theapplied insulating film material, the ultraviolet rays being applied tothe front face of the applied insulating film material in mixed gasatmosphere in which an inert gas and oxygen are mixed; and furtherapplying an insulating film material on the applied insulating filmmaterial after the ultraviolet-ray processing step.
 10. The substrateprocessing method as set forth in claim 1, wherein the ultraviolet raysis applied to the front face of the applied insulating material in theinert gas atmosphere while the substrate is held in a first area andthereafter in the oxygen atmosphere while the substrate is held in asecond area lower than the first area.
 11. The substrate processingmethod as set forth in claim 9, wherein the ultraviolet rays is appliedto the front face of the applied insulating material in the inert gasatmosphere while the substrate is held in a first area and thereafter inthe oxygen atmosphere while the substrate is held in a second area lowerthan the first area.